1. Field of the Invention
The present invention relates to Ultra-High Frequency ("UHF")/L-Band analog signal receivers. More particularly, the invention relates to monolithic integrated circuit direct digital receivers for receiving and processing analog signals in the UHF/L-Band range.
2. Description of Related Art
In various signal processing applications, it is necessary to receive analog signals and to derive a digitized baseband signal directly from a radio frequency ("RF") analog signal. At present, it is known in the art how to obtain direct digitization of RF signals using elements which exist separately. However, implementing a complete digital radio receiver on a monolithic integrated circuit, which has been a goal of receiver designers for some time, is not presently known in the art.
Certain technology limitations have prevented implementing a direct digital UHF/L-Band receiver on a monolithic integrated circuit. The fundamental stumbling block has been the performance of the analog-to-digital converter. Another stumbling block are limitations as to digital logic, i.e., processing the signal once it is digitized. If these stumbling blocks are overcome, however, one can implement a lower cost, complete direct digital radio receiver on a monolithic integrated circuit, which will have a lower parts count than a conventional analog receiver. Moreover, such a complete monolithic receiver will be digital and will thus have the advantages associated with digital circuitry, e.g., improved manufacturability, testability, predictability, etc. Finally, such a complete monolithic receiver will have improved selectivity compared to a conventional analog receiver, because the filtering employed in such a monolithic receiver is digitally implemented and thus capable of better performance than analog filters.
Therefore, a need exists for a complete, monolithic integrated circuit direct digital radio receiver for receiving UHF/L-Band frequencies and deriving digitized samples at baseband.